Why calories burned are a range, not a number
The calories you burn in a workout are an estimate, not a measurement — and the source of the numbers says so plainly. So WIMSTA shows a range, like “~300–390 kcal”, never a single figure pretending to be exact. It’s the same honesty as the ranges on our calculators.
The estimate comes from MET values
Burn is calculated with a standard formula: kcal/min = MET × 3.5 × weight(kg) / 200. The MET (“metabolic equivalent”) of each activity comes from the 2024 Adult Compendium of Physical Activities — the reference researchers use for the energy cost of human activity. A run has a MET; so does cleaning the house, or standing in a ceremony.
The source itself calls it an estimate
This is the part most apps hide: the Compendium’s own authors describe MET values as standardized estimates for a population, not exact figures for one person. Real energy cost varies by roughly 20–30% between people of the same weight — with fitness, technique, pace and even temperature. So the uncertainty isn’t our disclaimer; it’s the primary source telling you the number is approximate.
Source: Herrmann SD, Willis EA, Ainsworth BE, et al. 2024 Adult Compendium of Physical Activities. Journal of Sport and Health Science. 2024;13(1):6–12. doi:10.1016/j.jshs.2023.10.010. See data sources.
A range tells the truth; one number doesn’t
Showing “347 kcal” implies a precision no formula has. A range says what the estimate can actually support: somewhere in this band, probably. Strength training is rougher still — the MET of “lifting” barely reflects what you did between sets — so we mark it very approximate and treat the calories as secondary to the real record: your working weight over time.
How WIMSTA uses it
In your day, logged movement adds a burn range to “spent”, and the day’s balance (eaten − spent) stays a range too — never a verdict, nothing to “earn” or “burn off”. It’s part of the same principle across the whole site, explained on the method page: a range where the number is estimated, an exact figure only where it’s truly known.